What about wear and tear on your car!
I have been working in consulting for the last 4 years and I'm in South Africa. The way the companies that I have worked for over the last 4 years do it is, they charge a flat rate per kilometer that is driven which is worked out to cover all expenses for your car. These rates are worked out by taking the national average for business travel worked out by the AA and then a fixed amount is added onto that. So for example, if the AA state that an average cost for travel is X, then we add a small extra charge to that amount to accommodate for price increases.
When the SLA contract is first signed with the customer, they are made fully aware that the hourly rate is for work done and that the travel portion is a set figure. The travel portion will be the distance for a round trip from the office to the client and then back to the office. Then the customer knows, that should we do remote support the bill will be less, but should we need to do to their office, the travel will be added.
Working out this one has some pros and cons. On of the nice things is that, if you have many clients to see in the day, and you can manage your schedule correctly, you can score a little extra, as the travel cost is already agreed upon between the company and the client right at the beginning, and as you can guess, should you have one of those days were you are on the other side of town, you can't bill the customer more as the distance agreed upon is only from your office to theirs.
This seems to work out for the best for both the client and the company. Also with the charge being a bit above the national fuel average for distance traveled, this extra portion is to cover things like tires, services, oil etc.
